[IAUC] CBET 3966: 20140906 : SUPERNOVA 2014da IN NGC 128 = PSN J00291512+0251576

[quai en eps.harvard.edu]

                                                  Electronic Telegram No. 3966
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau en eps.harvard.edu (alternate cbat en iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


SUPERNOVA 2014da IN NGC 128 = PSN J00291512+0251576
     Further to CBET 3855, M. Kim, W. Zheng, and A. V. Filippenko, University
of California at Berkeley, report the LOSS discovery of a possible supernova
in NGC 128 on unfiltered KAIT images:

 SN       2014 UT       R.A. (2000.0) Decl.      Mag.      Offset
 2014da   Aug. 7.50    0 29 15.12  + 2 51 57.6   16.2    0".7 E, 7".2 N

A finding chart was posted by the discoverers at the following website URL:
http://astro.berkeley.edu/~zwk/findingchart/PSN_J00291512+02515763.jpg.  The
variable was designated PSN J00291512+0251576 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2014da based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2014da:  July 26.49 UT, 17.3 (KAIT); 31.47, 16.2 (KAIT); Aug. 8.061, 15.6 (G.
Masi, P. Catalano, and P. Schmeer; remotely using a 43-cm telescope at
Ceccano, Italy; position end figures 15s.13, 57".5); 8.796, 15.4 (J.
Brimacombe, Cairns, Australia; remotely using a 41-cm RCOS telescope + U9000
camera + luminance filter at the Warrumbungle Observatory, Siding Spring;
position end figures 15s.12, 57".8).  Brimacombe posted his images at
website URL https://www.flickr.com/photos/43846774@N02/14678067687/.  Masi
et al. add that several co-added low-resolution spectrograms of 2014da,
obtained Aug. 8.08 with a 36-cm telescope (+ 100 lines/mm grating; dispersion
3.45 nm/pixel) show Si II absorption around 621 nm, suggesting that this is a
type-Ia supernova; assuming a recessional velocity of 4241 km/s for the
host galaxy (NGC 128; via NED), an expansion velocity of about 11000 km/s is
derived from the minimum of the Si II 635-nm line.

     W. Zheng, I. Shivvers, H. Yuk, K. I. Clubb, and A. V. Filippenko,
University of California, Berkeley, report that inspection of a CCD
spectrogram (range 350-1000 nm), obtained on Aug. 26.334 UT with the Shane
3-m reflector (+ Kast spectrograph) at Lick Observatory, shows that PSN
J00291512+0251576 = SN 2014da is a type-Ia supernova.  Cross-correlation with
a library of supernova spectra using the "SuperNova Identification" code
(SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates a similarity with a
few 1991bg-like supernovae and a few normal type-Ia supernovae about 3-4 weeks
after maximum light.  However, the peak absolute magnitude of about -17.5
(adopting redshift z = 0.0141 and Galactic extinction A_R around 0.06 mag)
suggests a subluminous type-Ia supernova, consistent with the 1991bg-like
classification.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2014 CBAT
2014 September 6                 (CBET 3966)              Daniel W. E. Green